An alternative to proof of work?

[cafucafucafu]

Has there been any implementation of an altcoin which rewards proof of work to a maximum limit only? This way the maximum power of each node is capped.

[cryptworld]

there is proof of stake,  but some experts say that it is not as secure as proof of work

[ticoti]

take a look at this comparison  https://www.cryptocoinsnews.com/bitcoins-future-proof-of-stake-vs-proof-of-work/

you can also mix the systems but One thing is sure, bitcoin will never change its algorithm

[jonald_fyookball]

Has there been any implementation of an altcoin which rewards proof of work to a maximum limit only? This way the maximum power of each node is capped.

This doesn't seem possible.
 
How would the network uniquely identify a node?  By IP address? 
It is easy to get blocks of IPs and broadcast winning blocks from
any one of them.

And what's the motivation behind this idea?

[Flashman]

And what's the motivation behind this idea?

To return the means of production to the proletariat... probably.

[fordlincoln]

Proof of existence from Factom
Factom.org

[goosoodude]

Has there been any implementation of an altcoin which rewards proof of work to a maximum limit only? This way the maximum power of each node is capped.

I saw a variant of this suggestion some days back. Its not possible, anybody can set up multiple miners and go around it.